wavering
adjective
[ ˈweɪvərɪŋ ]
• moving in a quivering way; flickering.
• "a wavering flame"
• becoming weaker; faltering.
• "she gave a wavering smile"
waver
verb
• move in a quivering way; flicker.
• "the flame wavered in the draught"
• become weaker; falter.
• "his love for her had never wavered"
Origin:
Middle English: from Old Norse vafra ‘flicker’, of Germanic origin. Compare with wave.